The present invention relates to computer aided vehicle design in general, and more specifically to a method and system for computer aided vehicle to design using particle impact and soil deposition analysis.
There are numerous computer related tools which can facilitate the design and testing of automotive vehicles, including generalized software programs such as computer aided engineering (CAE), computer aided design (CAD), and computational fluid dynamics (CFD). These tools are typically used to investigate many issues related to vehicle design, including vehicle durability, vehicle performance, and vehicle aerodynamics. Heretofore, limitations on computer speed and algorithm accuracy have inhibited the development of a particle trajectory analysis tool in which several exterior aerodynamic design issues can be studied. For example, soil deposition on a vehicle panel due to tire rotation is a well known phenomena. A major obstacle in the past in investigating this, as well as other exterior aerodynamic issues, has been the inability to accurately calculate an external flow field around the vehicle.
However, with the advent of new and improved CFD technology, an accurate external flow field can now be calculated, thus making a particle trajectory analysis tool technically possible. A further need exists, nonetheless, for a method and system which utilizes available computer related technology to provide a user accessible particle trajectory analysis tool to aid in vehicle design. Additionally, a method and system is needed to provide a comparison between results from physical aerodynamic tests and a particle trajectory analysis tool, and to compare alternate vehicle designs.
The present invention addresses the deficiency in the field by providing a method and system for aiding in the design of an automotive vehicle enables dynamic placement of particle injection points relative to a computer aided design model representative of the vehicle to permit visual observation and alteration of resulting particle trajectories with respect to the model. Various particle trajectories, representing stones ejected from a tire toward the vehicle surface, soil deposition patterns along the bottom of vehicles, and the like can be simulated relative to the vehicle surface to evaluate a vehicle design, compare alternate designs and compare results from physical aerodynamic tests to predicted results.
The system of the present invention preferably comprises particle injector placement code operable with the user input means, such as a mouse, to effect a desired placement of at least one particle injector on the display with respect to a desired portion of a CAD model of the vehicle. Trajectory determination code means are included for computing at least one trajectory for a particle stream emanating from the at least one particle injector relative to the desired portion of the CAD model for a predetermined set of particle characteristics in a predetermined set of particle external conditions. The system also includes trajectory display code means for affecting display of the at least one trajectory with respect to the desired portion of the CAD model.
A method of the present invention comprises the steps of preparing a CAD model of the desired portion of the vehicle, placing a particle injector at a desired location with respect to the desired portion of the vehicle, specifying a set of particle information describing particles to be ejected from the particle injector, computing a stationary trajectory for a particle stream emanating from the particle injector, displaying the stationary trajectory relative to the desired portion of the vehicle on a display means to permit visual observation thereof, and repositioning the particle injector if necessary to achieve a desired stationary trajectory.
An advantage of the present invention is a method and system which permits modification of vehicle design based upon computed particle trajectories with respect to a CAD model of the vehicle.
Another advantage of the present invention is a method and system for aiding in vehicle design by enabling dynamic placement of particle injection points into a flow domain to permit visual observation and alteration of resulting particle trajectories with respect to a CAD model representative of the vehicle.
Still another advantage of the method and system of the present invention is a software program which allows a user to specify various characteristics of stones ejected from a tire patch to evaluate stone impact location and severity.
Another advantage is a software program for evaluating vehicle lower panel design relative to a stone and soil ejection from a vehicle tire.
Yet another advantage of the present invention is a method and system which provides a software program which can predict streaking along the bottom sides of a vehicle design caused by soil thrown from the tires.
Yet still another advantage is a software program which can predict soil deposition patterns from a vehicle tire and evaluate modifications to a vehicle design to minimize such streak patterns.